Propeller construction having integral hub reservoir



Jan. 26, 1954 A. N. ALLEN, JR

PROPELLER CONSTRUCTION HAVING INTEGRAL HUB RESERVOIR 5 Sheets-Sheet 1 Filed April 8, 1950 -|NVENTOR 91 K501 ATTORNEY.

4" A. N. ALLEN, JR 2,667,229

PROPELLER CONSTRUCTION HAVING INTEGRAL HUB RESERVOIR Filed April 8, 1950 5 Sheets-Sheet 2 INVENTOR ATTORNEY Jan. 26, 1954 A, ALLEN, JR 2,667,229

PROPELLER CONSTRUCTION HAVING INTEGRAL, HUB RESERVOIR Filed April 8. 1950 5 Sheets-Sheet 3 uumllmuulhIIIIIIHII- E6 a Q; B4 A: /4 /46 ATTORNEY Jan. 26, 1954 A. N. ALLEN, JR 2,667,229

PROPELLER CONSTRUCTION HAVING INTEGRAL HUBRESERVOIR Filed April 8, 1950 5 Sheets-Sheet 4 INVENTOR ATTORNEY Jan. 26, 1954 A. N. ALLEN, JR 2,667,229

PROPELLER CONSTRUCTION HAVING INTEGRAL HUB RESERVOIR Filed April 8, 1950 5 Sheets-Sheet 5 50 as v l C II II INVENTOR ATTORNEY Patented Jan. 26, 1954 UNITED STATESY PATENT F F ICE 'PROPELLER CONSTRUCTION HAVING INTEGRAL HUB RESERVOIR Arthur N; Allen, J r., Wethersfield; ComiQas'signor to United Aircraft Corporation,- East Hartford,

Conn., a'corporation of Delaware Application April 8, 1950, Serial No. 154,85?

6-Claims.

., I This invention relates to variablepitch propellers and more specifically to an improved-hub construction therefor.

It is an object of this invention to provide a propeller hub construction wherein an integral fluid reservoir is provided in the hub.

' A further object of this invention is to provide an'improved hub for a variable pitch propeller wherein the space between the propeller blade sockets is completely enclosed so as to form an integral fluid reservoir in the hub.

Another object of this invention is to provide an improved hydraulically operated variable -pitch propeller construction including a hub having the blade-sockets interconnected by integral closuremeans to form'wallportions for a self-contained chamber and a closure member forming an axially-spaced wall of the chamber whereby operating units for propeller operation and pitch variation are carried by the closure member and housed adjacent to the reservoir. A still further object of this invention is to provide a closure memberfor a self-contained fluidchamber in a propeller hub construction of the type described which carries hydraulic propeller operating units and fiuidpassages which provide fluid communicationwith the main bulb portion and pitch changing units when closure member is engageably positioned thereon.

-'These and other objects will become readily apparent from the following detailed description of the drawings in which:

Fig. l is a front view of the propeller hub construction of this invention with only aportion of the'propellerblades shown iorconvenience.

Fig.2 is a cross-sectional view taken along the line 22 of-Fig. 1 and'illustrating the hub including its associated, integral propeller operating mechanisms.

Fig. 3 is a rear view of the hub with its rear closure member removed.

' along the line 66 of Fig. 5 and illustrating the scavenge pump mounting and associated drive units assembled on the hub rear closure member.

Fig. '7 is a detail cross sectional. view taken along the line 7-! of Fig. 5 and illustrating the mounting of another of the propeller pump units.

Fig. 8 is a detail cross sectional view taken along the line 8'-8 of Fig. 5 illustratingthe passages leading fromthe main pump units to the propeller distributor valve.

Fig. 9 is a cross sectional view taken along the lineB-Q of Fig. 5 illustrating a passage from the main'pumping'system leading to the high pressure relief valve.

' Fig. 10 is a detail'cross sectional'view taken along the line I0l0 of Fig. 5 showing the high 1 pressure relief valve including the passages lead- Generally, the

ing'thereto and therefrom.

Figs. 11 and 12 are cross sectional views through ll'l'l and l2--l2 of Fig.5 showing oil passages leading from the distributor valve to the passages of the header ring which supplies the pitch change mechanism with hydraulic fluid.

Fig. 13 is a cross sectional view through the line l3'l3 of Fig. 5 indicating the sump relief valve. propeller and hub construction as illustrated and described in detail herein comprises a plurality of hydraulically operated variable-pitch propeller blades carried within the hub'. The blades contain hydraulic vane motors -=which--respond to fluid'pre'ssure in a manner that will become apparent hereinafter.

"Referring to Figs. 1 and 2, a hub 20 is shown having a plurality of propeller blades 22 mounted for pitch changing movement therein. As seen better in Fig. 2, the hub 20 is positioned on its drive shaft by'means of a front cone 24 and a rear cone which is not shown. The hub 26 comprises a-comp1etely integral main portion 30 having blade receiving sockets 32 and an interblade or intersocket webbing 34 which along with the sockets terminates in an annular shroud 36 which isspaced from the hub axis so as to form walls of acontinuous annular chamber or'sump 401 The shroud 36, whileforming a portion of the chamber 40, is tapered toward the forward end of .the entire assembly whereby it is readily adaptable to provide acontinuing streamline surface for apropeller spinner, a portion of which is illustrated inphantom at 44.

A more clear picture of the main hub portion is obtained by reference to Figs. 3 and 4 which .1- illustrate 'the previously mentioned hub main -portion 30 including its sockets 32, inter-socket web 34 andshroud 36. The main portion 39 also includes a cylindrical portion 56 which surrounds the propeller drive'shaft and has splines 51 on its internal periphery for engagement with said propeller drive shaft.

A closure member or'plate 50 is provided for sealing engagement with the hub main portion 36 to completely enclose the sump 46 and provide a fluid tight chamber which is integral with the propeller hub and which can be filled with fluid by removing the plugs M. Seals 5| are provided between the shroud 36 and the closure member 50 and seal 51a is provided between the main hub portion 36 and closure member 56 adjacent the internal periphery of the hub portion 36. As will become more clearly apparent hereinafter, the plate 56, while serving to-close ofi the sump 46, serves to carry the major pump and controlling units required for variable pitch operation so that these various units can be separately assembled on the plate 56 and subsequently readily fitted to the hub main portion 36 with great facility. Also, as will be seen hereinafter, the plate 56 includes the necessary fluid passages therein which place the various control units-in fluid communication with themain portion of the hub and pitch changing units merely by placing the plate 56 and it's accessories in engaging position with the main hub portion 36 and its integral shroud 36.

The closure plate 56 is mounted by studs 52a (Fig. 3) which are located within the ears 52 on the aft end of the shroud 36 of the main hub portion 36and screws 466 at its inner periphery as shown on Figs. 5, 6 and 7. r

In order to synchronize the pitch changing movement of all of the blades a bevel gear 2I6 is provided which engages gear segments 2I2 integral with the movable portion I18 of the blade vane motors.

r In order to provide mechanical pitch stops for the propeller blades a-pair ofstop rings 226 each having two lugs are splined to an extension 222 formed on the blade synchronizing gear 2 I 6. Cooperating stops are provided on a member 224 which is in turn splined with the main hub portion 36.

The blade synchronizing gear 2l6 further carries a depending ring gear 226 which drives a blade follow-up shaft 236. The follow-up shaft 236 is fixed for rotation within the main hub portion 36 and carries at its aft end a' driving gear 232. Hence, upon pitch changing movements of the propeller blades the shaft 236 and its gear 232 will, by means of a connector gear 234, rotate a valve return gear 236 which has a splined connection to a valve reciprocating member 240. Thus, pitch changing movements of the propellers will, by means of the follow-up mechanism and a worm connection described below,

7 cause thedistributor valve 96 to be repositioned. I

i In order to operate the previously mentioned 7 pumps and to control the pilotvalve 96; a controlling unit 256, illustrated in phantom in Fig. 2, is fixed to the adjacent power plant housing and contains governing units and a planetary gear system which does not form a specific part I of this invention and hence will not be described in detail. It will sufiice, however, to mention that during propeller rotation the gear 18, which has fixed thereto another gear 252 is normally held stationary by means of interconnections with units in the control housing so that the pump units fixed to the closure member 56 will be operated as they revolve around the gear 18. The entire control assembly is further supported on the main hub portion 36 by ball bearings 254 so that the hub may rotate while the control unit may remain stationary. 7

A distributor valve drive gear assembly 256 is also provided and has at its forward end a gal 258 and at its aft end a gear 266. The gear is operatively connected to the planetary gear system within the control housing in such a manner that, for an on-speed condition of the propeller. gear 256 will normally rotate in phase with the propeller. Therefore, the gear 258, which is connected to a valve operating gear 262, will maintain a position relatively fixed to the propeller. Gear 262, restrained from axial movement by its mounting, has a screw thread connection with valve reciprocating element 246. It is apparent therefore that when there is no pitch change demandor response gear 236 is held stationary and thus the screw member 246 will maintain" valve 'member 96 in a fixed position.

However, in the event that a pitch change is called for by control unit or governor in the housing 256 T the planetary system therein will cause the valve drive assembly 256 through its gear 266 to change its phase relation with the propeller and hub. This relative rotation will cause the gear 258 to rotate the gear 262 and through'the worm connection 264 cause the valve 96 to-move nism described will tendto reposition the valve in a neutral position. a

The arrangement of the various pitch operating and control units which are carried by the closure member or plate 56 is best seen in Fig. 5. These units comprise "a high pressure pump 60 and a stand-by high pressure pump 62. -The outlets of these pumps are connected to the pilot valve 96 for proper high pressure fluid distribution to the pitch change units I18 (Fig. 2) and to a high pressure relief valve 64 which limits the high operating pressure at a desirable level by dumping excessive fluid back into the sump 46. A scavenge pump 66 is also provided which picks up fluid that may accumulate in the chamber 68 (see also Fig. 2) located immediately aft of the closure member '56. It will sufiice atthis point to mention that chamber 68 is at atmospheric pressure. The chamber 68 is defined by the closure plate 56 and a backing plate 69 which is attached to the hubby means ofthe studs 52a (Fig. 4) so as to engage the outer periphery of the closure'plate 56 in the manner shown in Fig. 4. The studs 52a pass through a plurality of bosses (not shown) spaced adjacent the periphery of the closure plate 56'so that'the backing plate '69 mates accurately with the plate'56 where thestuds are located. A slight clearance may exist, then; between the adjacent faces of the plates 56 and 69 in the peripheral spaces between adjacent studs.

The scavenge pump 66, as better seen inFig. 6 fits into a cavity in the closure member 56 and takes in fluid from the chamber 68 via an inlet passage 16 and discharges the fluid into the pressurized sump 46 via an outletpassa'ge 12. The passages 16 and F2 are formed within .the' plate member 56. The pressure in the sump 46 is controlled by a relief valve 462 (Fig. '13) also mounted in plate 56. Excess of pressurized fluid or oil is thereby relieved from the sump to'the atmospheric chamber 68. 'An idler gear 14 journalled in the closure member 56 provides a driving connection between the scavenge pump drive gear 16 and a normally stationary gear 18. The idle gear 14 includes 'a hollow shaft 86 which receives fluid under sump pressure'from a passage aesrgaea lubricating fluid 'formspar-t'of thefluid accumu lation in the chamber- 68 Y A lubricating valve 83 (Fig.5) provides" furtherlubrication to the other gears located within-thechamber 68.

Fig. 7 illustrates one of the high pressure pumps which has its driving gear 86 connected to the previously mentioned normally stationary gear 18. Fluid enters the pump from the pressurized'sump through'an inlet paSsageBB and discharges this highpressure fluid-into high pressure passages leading to the distributor valve'flfl (Fig. 8) forproper apportionment of the fluid to the propeller pitch changing mechanism. 1 As' seen in Fig. 8, the distributor valve receives fluid from'the' main high pressure pump 6 0 via a passage 92 and also from the stand-by pump '62 via a passage 94. Although both pumps and 62 are continuously operating, when the distributor valve9U is in its neutral position or when the blades are responding sufiiciently rapid to small controlling movements of the distributor valve 90, fluid from the'stand-by pump; which enters the valve by means of the passage 94, flows through the pump housing pass-age 96, past "the valve land 98 and through the hole' I 00. The fluid is then discharged through the core of the valve'fifl into the pressurized sump 40. In this manner, only when greater volume is necessary, does the discharge from the stand-by pump come into play. In other words, the output of both Dumps 60 and 62 will be utilized for pitch change when rapid-movements arecalled for by the valve mechanism 90 previously described.

As seen in Fig. 9, the high pressure pump is connected to a passage IE4 which in turn'leads to a passage I96, seen in Fig; 10, communicating with the relief valve fi lfi'The'relief valve 64 includes a valve member I08 whichliasf its upper end operatively connected to a plurality of Belleville washers III]. In this'way the valve member I08 will have'a snap action so that it will pop open and close at a'rapid speed so as m relieve fluid pressure from the passage I06 out through the passagel I 2 and eventually to the pressurized sump 40.

Returning to Fig. 2, the distributer valve 9i] is also in communication with a stand-by check valve I20; The purposeof this valve'is to bring into operation the additional capacity of the stand-by pump '62. Thus; when movements of the distributor valve 98 arerelatively large (indicating a lack of response in propeller pitch change) so that additional fluid is necessary-for adequate propeller pitch variation,- the' fluid from the stand-by pump will; instead of being dumped into the'sump'fifl as previously described be forced through the passage I22 leading from the valve 90 into the check valve I20; then past the ball check. and via the passage I24'ba-ck to the distributor valve throughthe passage I26 located in the distributor valve housing. This passage I26, which is also seen in Fig. "8',.it willbe n'oted, provides additional fluid to the" valve simultaneously'with the fluidcoming from the main pump 60 via the passage 92;

In order to follow the high pressure flowfrom the distributorvalve '90, Which flow is used to vary the pitch of propeller blades, it is best to refer to Figs. 11 and '12. -Thus,'for-one pitch changing direction fluid under pressure is passed via the passage I39 throughthe passages I32 and I34 to an =oper'1ingil36 which leads to an annular transfer passage I38in a header ring I40 which ring in turn distributes fluid .under pressure to the pitchchanging motorsnlocatediin eachof the in the other direction (Fig. 12) fluid under-pressure from-the distributor valve I m-passes to a pas. sage I as which is spaced from the previously mentioned passage I 38 circumferentially "about the axis of distributor valve 96. Fluid under pressure from the-passage I44 then flows via the passages I56, I48 and the port I50 into the second annular transfer passage I52 in the header ring I40 from whence'it ispasse'd to each of the pitch changing motors in the propeller blades to vary the pitch in another direction.

It will be noted thatthe high pressure passages 13$ and IE4 (Figs. 11 and 12) leading from the valves!) are drilled within the valve housing and have their forward ends plugged with inserts I56. It will be further noted that a fluid tight connectionbetwe'en passages I32 and I34- (Fig? 11) and between passages I i-E5 and I48(Fig 12) com pleted-upon positioning of the closure plate 50 upon the rear of the hub portion 30 by means of sleeves I58 and I59 which have a pressed fit into the ports I35 and I48, respectively; Hence the aft extending portions of the sleeves will engage the'inner periphery of the seals IBBand also the coupling member I6! which carries the seals whereby a fluid tight high pressure connection is obtained upon installation of the closure plate 50.

r The passage of fluid from the header ring Id'fl'i's best seen'in Fig. 2. a As viewed herein, it can be seen that the annular'chambers I38 and I 52 in the header ring I49 communicate: with mating passages in a fluid transfer screw-I10 which is located centrally of the stationary portion I'M of a vane motor located'within the base of each of the propeller blades 22. The fluid-under pressure passes from the transfer-screw I10 to either side of the vanes in the motor so that the passages I38 and IE2 may alternately serve as pressure or drain conduits. The'stationary vane motor portion I'M is held fixed by means of a toothed connection with the main hub portion 30 as indicated at I16; The movable portion I18- of the vane motoris splined at into the inner periphery of the blade shank so that its motion is transmitted to the blade to vary the pitch thereof.

The transfer screw' I-Hl is more fully described and claimed in copending patent application serial No. 149,545; filed March '14, 1950, by Earl M. Frankland.

Each of the propeller blades 22 isretained'within the blade socket. 32 by means of a plurality of ball bearings I84 which engage integral races formedon the inner periphery of the blade socket 32 and on the outer periphery of the shank of blade 22. Thebearings are inserted through a plurality of holes I'86 which are providedin the sides of the sockets 32. In order to preload'these bearings'a nut I9flisprovided'at the base of the blade surrounding the bottom of the fluid transfer screw I10 so that the blade 22 may be forced outwardly.

The holes I86 for inserting the ball bearings I84 which are located on the aft side of socket 32 (right side as viewed in Fig. 2) are provided with hollow insert plugs I98 so as to permit fluid communication between the pressurized sump 40 and a second annular. chamber 404' adjacent the base of the blades for lubricating purposes. The heads of the plugs :I90 are large enough in diameter so that the projections=I92 on the forward faceof the closure member 56 will retain all of theiplugs :IS'IJ in position as illustrated. The retaming plugs I96 on the forward side of the socket 3.2yhave overlapping heads so that a clamp I98 boltedto the front-of the hub will retain all of the plugszin place by bearing only" on one of them asshown. '3

-In'order to seal off the second annular chamberat the base of the blades (inasmuch as-the fluid therein will be under sump pressure) a cover plate 200 is provided at the forward end of the main hub portion and is connected thereto by means .of bolts 202. The propeller retaining nut 264 has a sealingengagement with the cover plate 200 and with the header ring MI! by means of the seals 206 and 406. Combined with the sealing elements between the blade sockets 32 of hub 30 the above-mentioned seals serve to completely close ofi the blade lubricating chamber.

,In order to seal the chamber 68 which is at atmospheric pressure a running rubber seal 280 is provided which has a substantially U cross sectional shape and is held fixed against rotation to the control housing 250 by a garter type spring. A spreadable spring steel collar 282 is positioned intermediate the garter spring and the seal 280 so that the spring pressure will tend to spread the free ends of the U shaped seal 288. A pair of depending seal engaging members 284 and 286 straddle the seal 280 and are fixed for rotation with the hub. Any fluid that may pass between the seal 280 and the engaging member 284 will be centrifuged back into the chamber 68 by means or other causes which may influence the pitch changing movements of the blades so that the blades tend to move toward a low pitch position while the distributor valve 90 is calling for a high pitch, an automatic pitch lock mechanism is provided. The pitch lock consists of an axially slideable'annular cylinder 300 which is located forward of the header ring I40 and is biased in a forward direction by a plurality of coil springs 302. The forward end of the piston 300 has ratchet type teeth which mate at 304 with similar teeth on the blade synchronizing gear 2). During normal operation fluid under pressure in chamber 396 tends to maintain the piston in a disengaged position by forcing it aft against the bias of springs 352. The fluid under pressure for chamber 305 is obtained from the passage 3! which surrounds th follow-up shaft 230 and the passage 312 which is in communication with drain pressure in the central portion 3H5 of the distributor valve 90. This pressure is maintained at some predetermined value slightly above the pressure existent in the sump 40 by means of a pitch lock relief valve 3|6 which in its relieving operation dumps excessive fluid directly into the sump 40. In th event that the propeller blades are tending to go toward a low pitch and in responding to a call for high pitch by the distributor valve 90 the passage 3l2 will be opened to the passage 318 rather than to the drain pressure in the distributor valve so that any pressure existing in the passage 3l2 will be relieved into the chamber 68 which is at atmospheric pressure. .Relief of pressure in this manner will immediately relieve the pressure in the chamber 306 which is acting on the piston 360 so that the springs 302 will cause engagement of the ratchet teeth on the piston 30B and the synchronizing gear-2l ll, The ratchetteeth 'mentionedare of suchshape that they will permit movement of the bladesftoward high pitch whiletheywill lock them against movement towardlow. pitch. Thus, should pressure be restored intermittently or should sufficient pressure be attained to operate the pitch changing mechanism, movement toward high pitch will be immediately attained even though suificient drain pressure may not have as yet built up to disengage the teeth on the lock piston 300.

The pitch lock system described may be of the type more fully described and claimed in patent application Serial No. 129,082, filed November 23, 1949, by Erle Martin and Thomas Rhines and in patent application Serial No. 128,955, filed November 23, 1949, by John E. Anderson which matured into Patent No. 2,635,702.

Thus, as a result of this invention it is readily apparent that a completely operative propeller unit has been provided which is substantially integral with the unitary rotating hub to form a compact mechanism while providing a self -contained fluid reservoir within the rotating hub.

Also, it is evident that a closure member has been provided to seal-01f the integral reservoir which closure member upon being positioned provides the necessary communicating passages to the pitch changing mechanisms while further carrying the pitch changing pump and control units.

Further as a result of this invention an integral fluid reservoir has been'provided within the propeller hub by utilizing the inter-blade space so that the main hub portion forms a majority of the reservoir walls thereby a single plate-like closure member can be readily attached thereto in operative position without the necessity of numerous assembly steps.

Although only one embodiment of this invention has been illustrated and described herein, it is obvious that various changes and modifications will be made in the arrangement and construction of the various components without departing from the scope of this novel concept.

What it is desired to secure by Letters Patent is:

1. Ina variable pitch propeller, a unitary hub portion comprising a central member extending along the axis of propeller rotation and adapted to engage a propeller driving shaft, blade receiving sockets extending outwardly from said central member, closure means spanning the space between said sockets, and a shroud coaxially disposed in spaced surrounding relation with said central member and engaging the outer periphery of said closure means to form an annular chamber, a closure member axially spaced from said closure means and engaging said shroudand said central member for sealing said chamber including hydraulic units carried thereby and integral fluid passages therein, propeller blades mounted for pitch changing movements in said sockets and including pitch changing units therein, and passage means carried by said unitary hub portion providing fluid communication between said pitch changing units and said hydraulic units including connecting means providing fluid tight connection between said units.

2. In a variable pitch propeller, a unitary hub member comprising radially extending blade receiving sockets and closure means spanning the space between said sockets thereby forming a wall substantially transversely of the axis of rotation of the hub, said unitary member including a shroud spaced from said axis and extending along said axis, said shroud engaging said wall, a closure member cooperating with said shroud and axially spaced from said wall forming a first fluid confining chamber within the hub, propeller blades mounted for pitch changing movement within said sockets, said blades terminating at their inboard ends in radially spaced relation with the hub axis thereby forming walls of a second chamber, means engaging said unitary member to enclose said second chamber, pitch changing means for said blades, first passage means in said socket providing communication between said first and second chambers, control mechanism supported by said closure means for operating said pitch changing means including means for withdrawing fluid from said first chamber, and second passage means carried by said closure means providing fluid communication between said control means and said pitch changing means.

3. In a variable pitch propeller, a hub comprising a central member extending along the axis of propeller rotation and adapted to engage a propeller drive shaft, blade receiving sockets extending radially from said central member, webbing spanning the space between said sockets and forming a wall, an annular shroud extending in an aft direction from adjacent the outer periphery of said webbing and the outer extremities of said sockets, and a closure plate engaging the aft end of said shroud and central member forming a first chamber, blades mounted for pitch changing movement in said sockets with the inner end of the blades radially spaced from said central member forming a second chamber, and passage means in the walls of said sockets providing communication between said chambers.

4. In a variable pitch propeller according to claim 3 including pitch changing fluid motors in the base of said blades, control mechanism carried by said plate and passage means leading to said motors and said control mechanism.

5. In a propeller according to claim 1 having a low pressure chamber communicating with said hydraulic units, said low pressure chamber com prising, a chamber wall section fixed to said hub unit and rotatable with the propeller, a control housing fixed against rotation and located adjacent to said Wall section and sealing means engaging said wall section and said fixed control housing.

6. In a variable pitch propeller, a hub comprising a central member extending along the axis of propeller rotation and adapted to engage a propeller drive shaft, blade receiving sockets extending radially from said central member, webbing spanning the space between said sockets and forming a wall located in a plane on one side of the center lines of said sockets, an annular shroud having one end located adjacent the outer periphery of said Webbing and the outer extremities of said sockets and extending along the axis of propeller rotation, and a closure plate engaging the other end of said shroud and central member, said closure plate being located in a plane on the other side of the center line of said sockets, whereby said central member, said webbing, said shroud and said closure plate form a sump chamber between and in the plane of said sockets and said central member forms a closure for the inner ends of said sockets and separates said sockets from said chamber.

ARTHUR N. ALLEN, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,425,261 Murphy et a1. Aug. 5, 1947 2,462,932 Anderson Mar. 1, 1949 2,466,775 Martin Apr. 12, 1949 2,491,375 Hardy Dec. 13, 1949 2,501,432 Booth Mar. 21, 1950 2,513,156 Eaves June 27, 1950 2,515,037 Hardy July 11, 1950 FOREIGN PATENTS Number Country Date 703,319 Germany Mar. 6, 1941 

